If it costs more than $87, you'll never get your money back.
This is rubbish due to one variable - BTC price.
Why can't people get that fact in to their thick heads?
Then let's run the numbers.
Right now we have an estimate this will be available to ship November 14th, this assumes it is in the hands on resellers/"group buy" organizers, etc. With lead time like that and no apparent details I'll safely assume you're looking more at the end of November to have this in-hand. If so, at the current price of 1.99BTC the value of this for someone who doesn't have BTC and wants to buy one is ~$480 as of market conditions this morning.
If you start with USD, your only hope is that this sucker produces as expected by any traditional calculator and that BTC goes up by at least another 30% or more to make it ROI per the fiat originally used for the purchase. Alternatively, buy the 1.99BTC and hold since the unit will never produce that much BTC before you're paying more in power than the unit is producing, at which case, still, buying would get you 1.99BTC today and you don't have to get involved in that waiting/speculation game.
If you start with BTC, you are doing the old "Here's 1.99BTC, hopefully I'll get back 1.5BTC of that!". In that case, if you have BTC it is better to hold the BTC, otherwise you're basically donating to FriendCat and whichever reseller you're purchasing from.
That's what people need to get through their thick heads.